Access to the UV range is fundamental for astrophysics since thermal phenomena at temperatures T>10,000 K occur in a wide range of astophysical events, with flux emission mostly in the UV. Moreover, UV spectroscopic and imaging capabilities are a fundamental tool to study plasmas at temperatures in the 3,000-300,000 K range. Also, the electronic transitions of the most abundant molecules in the Universe (H2, CO, OH, CS, CO2+, CO2) are in the UV range. The UV radiation field is also a powerful astrochemical and photoionizing agent.
The ozone layer of the Earth's atmosphere that protects life on Earth from the ultraviolet (UV) radiation of the Sun at the same time prevents ground-based astronomical UV observations. So the most information on UV radiation of celestial objects come from space observatories.
The scientific plans for WSO-UV are very ambitious, and span all of the astronomical research branches. WSO-UV will be operating in the second decade of this century, and it will be a fundamental tool for the development of astronomical knowledge, fully integrated with the many other space and ground-based observatories.
We expect that WSO-UV will open new opportunities in planetary science, stellar astrophysics, extragalactic astronomy and cosmology. With its launch date in 2016, WSO is ideally placed to provide follow-up studies of the large number of UV sources found by the GALEX sky survey after the end of the HST mission.